Sample analyzer and sampling system

ABSTRACT

A spectroscopic sample analysis apparatus includes an actively controlled, direct contact heat exchanger in serial fluid communication with a spectroscopic analyzer, and a controller communicably coupled to the heat exchanger. The heat exchanger is disposed downstream of a fluid handler in the form of a stream selection unit (SSU), a solvent/standard recirculation unit (SRU), and/or an auto-sampling unit (ASU). The SSU selectively couples individual stream inputs to an output port. The SRU includes a solvent/standard reservoir, and selectively couples output ports to the heat exchanger, and returns the solvent/standard sample to the reservoirs. The ASU includes a sample reservoir having a sample transfer pathway with a plurality of orifices disposed at spaced locations along a length thereof. The controller selectively actuates the fluid handler, enabling sample to flow therethrough to the heat exchanger, and actuates the heat exchanger to maintain the sample at a predetermined temperature.

RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application Ser.No. 60/848,936, entitled Sample Analyzer and Sampling System, filed onOct. 3, 2006, the contents of which are incorporated herein by referencein their entirety for all purposes.

BACKGROUND

1. Technical Field

This invention relates to the measurement of chemical and physicalproperties of flowing streams of liquids, solids or mixed liquids andsolids by quantitative nuclear magnetic resonance (NMR) spectroscopy,but may be applied to other types of molecular spectroscopy includinginfrared (IR), near-infrared (NIR), and Raman spectroscopy. Inparticular, this invention relates to sample analyzers and systems formanaging sample introduction into the analyzers.

2. Background Information

The analysis of materials using NMR requires a region of spacecontaining a magnetic field that is either extremely uniform in magneticflux density or else extremely uniform in the spatial gradient ofmagnetic flux density. In such a region, a sample to be analyzed issubjected to a short pulse of electromagnetic energy at a predeterminedfrequency that is a function of the atomic nuclei to be analyzed and oftheir chemical bonding. The pulse is coupled to the sample by a surfacecoil. A typical pulse duration is of the order of fifty microseconds,although the pulse width that is chosen is a function of thecharacteristic relaxation time of the subject nuclei in material beinganalyzed. The magnetic field causes the magnetic moments of theconstituent nuclei in the sample to become aligned along lines ofmagnetic flux. If the field is strong and uniform to a relatively highdegree of precision, the magnetic moments will be essentially parallelto each other, resulting in an aggregate or bulk magnetic moment. Theelectromagnetic energy coupled to the sample effects a change in thebulk magnetic moment. The relaxation of the bulk magnetic moment fromthe re-aligned position back to the original position when the pulse isended produces signals that may be detected and transformed into aspectrum, in which response intensity plotted as a function of frequencyis unique to the particular sample composition. Due to the temperaturedependence of both the consistency of the magnetic field and a sample'sspectral behavior, temperature control of both within appropriatetolerances is desired.

NMR spectrometers came into use in the research laboratory in the early1960s. As NMR technology advanced, it became a ubiquitous tool forelucidating molecular structure, chemical behavior and reactionmechanisms, and molecular level interactions in biological systems anddiverse organic molecules including pharmaceuticals and polymers.Generally such investigations are performed on pure materials orcarefully controlled mixtures to permit observation of the chemicalphenomenon of interest. Understanding about the chemistry may be deducedthrough examination by a skilled spectroscopist of features in a singlespectrum or a series of spectra measured on the subject chemical systemunder limited number of experimentally controlled conditions.

More recently, NMR analysis has also been used in various productionenvironments to analyze flowing liquids, pastes, slurries, or solids inpowdered or other finely divided form. NMR analyzers may be used toperform in minutes the measurement of multiple chemical and physicalproperties, which otherwise would need to be analyzed by many differentanalytical methods in a quality control laboratory, requiring hours oreven days. This capability to perform multiple analyses with highfrequency automatically, makes process NMR analysis a cost-effectivemeans for characterizing input and output streams associated withdiverse chemical processes. A typical NMR analyzer commonly used forsuch process applications includes the D-Mash NMR analyzer availablefrom The Qualion Company, Haifa Israel.

Process streams that may be difficult to analyze continuously by meansother than NMR include those which have high optical density, highloading of fine particulates or solids, high water content, orrelatively high viscosity. Exemplary applications therefore may includethose in oil and petrochemical processing plants, chemical plants, andother industries requiring automatic process control of fluids. In thepetrochemical field, these analyzers have been used in crude blending,fast CDU optimization after crude feed switching, effective feed controland optimization of FCC (Fluid Catalytic Cracking) unit applications.Other industries that may benefit from NMR analyzers include plasticsand polymers, pharmaceuticals, food and beverages.

In contrast to traditional use of analytical NMR spectroscopy inresearch applications, petrochemical streams can contain dozens orhundreds of compounds. Accordingly, the objective is no longerstructural elucidation or detailed chemical characterization, but themeasurement of bulk properties such as distillation yields at varioustemperatures, the total aromatic content, acidity, bulk sulfur content,octane in gasoline, cetane in diesel, and cloud point in jet fuel. Also,the analysis of a sample spectrum to obtain property values is performedautomatically by software, which applies property-specific models basedon data sets of dozens or hundreds of calibration samples whose spectrawere measured previously and corresponding property values analyzed inthe laboratory.

It follows that the quality of property models depends at a minimum onthe compositional diversity of the calibration sample set and theprecise measurement of NMR spectra. The latter requires proper tuning ofthe NMR spectrometer to achieve a magnetic field of suitable uniformityand the supply to it of samples maintained at relatively uniformtemperature. For example, even relatively slight variations in sampletemperature, e.g., variations as small as plus or minus 3 degrees C.,may significantly reduce measurement accuracy. A set of calibrationsamples whose compositional diversity is suitable for creation ofproperty models may be obtained most conveniently by collecting andstoring samples over a relatively long time frame during which feed orproduct streams associated with a process exhibit relevant propertyvariations.

A need therefore exists for an apparatus and method for maintaining andsupplying samples to an NMR analyzer in a relatively uniform state, bothon-line within a process, and off-line in a batch processing mode.

SUMMARY

One aspect of the present invention includes an apparatus for sampleanalysis. The apparatus includes an actively controlled, direct contactheat exchanger configured for upstream serial fluid communication with amagnetic resonance analyzer, and a controller communicably coupled tothe heat exchanger. The heat exchanger is placed downstream of at leastone fluid handler. The fluid handler is selected from the groupconsisting of a stream selection unit (SSU), a solvent/standardrecirculation unit (SRU), and an auto-sampling unit (ASU).

The SSU includes a plurality of stream input ports, a stream outputport, and one or more SSU valves configured to selectively coupleindividual ones of the stream input ports to the stream output port. Thecontroller is configured to selectively actuate the SSU valves to selectand couple a stream source to the stream output port, and actuate theheat exchanger to maintain a sample of the stream source at apredetermined temperature.

The SRU includes one or more solvent/standard reservoirs, a fluid outputport associated with each of the reservoirs, and one or more SRU valvescoupled to the output ports, to selectively couple an individual one ofthe fluid output ports to the heat exchanger. The controller isconfigured to selectively actuate individual ones of the SRU valves tocouple a reservoir to the heat exchanger, and to actuate the heatexchanger to maintain a sample of solvent/standard at a predeterminedtemperature for input into the analyzer. A return line is configured toreturn the solvent/standard sample to the reservoirs from the analyzer.

The ASU includes one or more sample reservoirs configured to storesamples therein, and a sample port respectively coupled to each of thereservoirs. The sample reservoirs each have a sample transfer pathwaycoupled to the sample port and extending into the reservoir, the pathwayhaving a plurality of orifices disposed at spaced locations along alength thereof. One or more ASU valves selectively couple the sampleport to the heat exchanger. The controller is configured to selectivelyactuate the ASU valves to enable a sample to flow through the samplepathway to the heat exchanger, and to actuate the heat exchanger tomaintain the sample at a predetermined temperature.

In another aspect of the invention, a sample handling apparatus includesa stream selection unit (SSU). The SSU includes a plurality of streaminput ports, a stream output port, and one or more SSU valves configuredto selectively couple individual stream input ports to the stream outputport. A pump is disposed in serial fluid communication with the streamoutput port, and an actively controlled, direct contact heat exchangeris located in series with the stream output port. A controller isconfigured to selectively actuate the pump and the SSU valves to selectand couple a stream source to the stream output port, and actuate theheat exchanger to maintain a sample of the stream source at apredetermined temperature for input to a magnetic resonance analyzer.

In still another aspect of the invention, a sample handling apparatusincludes a solvent/standard recirculation unit (SRU). The SRU includesone or more solvent/standard reservoirs, a fluid output portrespectively associated with each of the reservoirs, and one or more SRUvalves coupled to the output ports, to selectively couple an individualone of the fluid output ports to the heat exchanger. A pump and heatexchanger are located in serial fluid communication with the fluidoutput port. A controller is configured to selectively actuateindividual SRU valves to couple the solvent/standard reservoirs to theheat exchanger, to actuate the pump, and to actuate the heat exchangerto maintain a sample of solvent/standard at a predetermined temperaturefor input into the analyzer. A return line is configured to return thesolvent/standard sample to the reservoirs from the analyzer.

In yet another aspect of the invention, a sample handling apparatusincludes an auto-sampling unit (ASU). The ASU includes one or moresample reservoirs configured to store one or more samples therein, and asample port respectively coupled to each of the reservoirs. The samplereservoirs each have a sample transfer pathway coupled to the sampleport and extending into the reservoir. The pathway has a plurality oforifices disposed at spaced locations along a length thereof. Anactively controlled, direct contact heat exchanger is located in serieswith the sample port, and one or more ASU valves are configured toselectively open and close a fluid flow path between the sample port andthe heat exchanger.

A controller is configured to selectively actuate the ASU valves toenable a sample to flow through the sample pathway to the heatexchanger, and to actuate the heat exchanger to maintain the sample at apredetermined temperature.

The features and advantages described herein are not all-inclusive and,in particular, many additional features and advantages will be apparentto one of ordinary skill in the art in view of the drawings,specification, and claims. Moreover, is should be noted that thelanguage used in the specification has been principally selected forreadability and instructional purposes, and not to limit the scope ofthe inventive subject matter.

In still another embodiment, a method of sample analysis includesdisposing an actively controlled, direct contact heat exchanger inupstream serial fluid communication with a sample analyzer, communicablycoupling a controller to the heat exchanger, and disposing the heatexchanger in serial fluid communication downstream of at least one fluidhandler selected from the group consisting of a stream selection unit(SSU), a solvent/standard recirculation unit (SRU), and an auto-samplingunit (ASU).

The SSU includes a plurality of stream input ports, a stream outputport, and one or more SSU valves configured to selectively coupleindividual ones of the stream input ports to the stream output port. Thecontroller is configured to selectively actuate the SSU valves to selectand couple a stream source to the stream output port, and actuate theheat exchanger to maintain a sample of the stream source at apredetermined temperature.

The SRU includes one or more solvent/standard reservoirs, a fluid outputport associated with each of the reservoirs, and one or more SRU valvescoupled to the output ports, to selectively couple an individual one ofthe fluid output ports to the heat exchanger. The controller isconfigured to selectively actuate individual ones of the SRU valves tocouple a reservoir to the heat exchanger, and to actuate the heatexchanger to maintain a sample of solvent/standard at a predeterminedtemperature for input into the analyzer. A return line is configured toreturn the solvent/standard sample to the reservoirs from the analyzer.

The ASU includes one or more sample reservoirs configured to storesamples therein, and a sample port respectively coupled to each of thereservoirs. The sample reservoirs each have a sample transfer pathwaycoupled to the sample port and extending into the reservoir, the pathwayhaving a plurality of orifices disposed at spaced locations along alength thereof. One or more ASU valves selectively couple the sampleport to the heat exchanger. The controller is configured to selectivelyactuate the ASU valves to enable a sample to flow through the samplepathway to the heat exchanger, and to actuate the heat exchanger tomaintain the sample at a predetermined temperature.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of this invention will bemore readily apparent from a reading of the following detaileddescription of various aspects of the invention taken in conjunctionwith the accompanying drawings, in which:

FIG. 1A is a schematic block diagram of a system in which exemplaryembodiments of the present invention may be used;

FIGS. 1B-1D are schematic block diagrams of variations of the system ofFIG. 1A;

FIG. 1E is a schematic view of a portion of an embodiment of the presentinvention;

FIG. 2 is a schematic view of another portion of an embodiment of thepresent invention;

FIG. 3 is a schematic, perspective view of another portion of anembodiment of the present invention;

FIG. 4 is a schematic view, on an enlarged scale, of a portion of theembodiment of FIG. 3;

FIGS. 5 and 6 are plan and top plan views, on an enlarged scale, ofportions of the embodiment of FIG. 4;

FIG. 7 is a schematic, on an enlarged scale, of a portion of theembodiment of FIG. 4;

FIG. 8 is a schematic view of yet another embodiment of the portionsshown in FIG. 4; and

FIG. 9 is graphical representation comparing sample before and afterbeing processed by embodiments of the present invention.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings that form a part hereof, and in which is shown byway of illustration, specific embodiments in which the invention may bepracticed. These embodiments are described in sufficient detail toenable those skilled in the art to practice the invention, and it is tobe understood that other embodiments may be utilized. It is also to beunderstood that structural, procedural and system changes may be madewithout departing from the spirit and scope of the present invention.The following detailed description is, therefore, not to be taken in alimiting sense, and the scope of the present invention is defined by theappended claims and their equivalents. For clarity of exposition, likefeatures shown in the accompanying drawings are indicated with likereference numerals and similar features as shown in alternateembodiments in the drawings are indicated with similar referencenumerals.

Embodiments of the present invention include sampling devices that maybe used alone or in combination with one another to provide consistentlyhomogeneous samples to an analyzer such as an NMR analyzer (alsoreferred to herein as a Magnetic Resonance Analyzer or MRA) in bothonline and offline applications. In various embodiments discussedherein, a suitable MRA includes the aforementioned D-Mash NMR analyzerfrom Qualion. Each of the various embodiments discussed hereinbelowdeliver a fluid to the MRA at a predetermined set point temperatureapplicable for a particular application, while maintaining the set pointtemperature within a predetermined, relatively tight, tolerance. Forexample, a temperature of 40° C. might be selected for gasolineanalysis, while FCC feed or crude oil samples generally are analyzed at80° C.; in both of these examples, the temperature tolerance on sampleflowing to the MRA is ±2.5° C. In should be recognized that althoughembodiments of the present invention are shown and described withrespect to a nuclear magnetic resonance (NMR) spectroscopic analyzer,they may also be applied to other types of spectroscopic analysis, suchas spectroscopy including infrared (IR), near-infrared (NIR), and Ramanmolecular spectroscopy

Embodiments of these devices are presented in Sections A, B, and Cbelow, in connection with the appended Figures, and include a StreamSwitching Unit (SSU) 10, 10′ (FIGS. 1A-1E), a Solvent (Sample)Recirculation Unit (SRU) 12, 12′ (FIGS. 1A-1E, 2), and an Auto-SamplingUnit (ASU) 14, 14′ (FIGS. 1A-1E, 3). As described in greater detailbelow, representative embodiments of the SSU are used to receive andselect between process samples arriving at the SSU (e.g., viaconventional fast loops). By contrast, the ASU permits offline analysisof multiple samples through their injection into the MRA 16 (FIG. 1)from sample cylinders. The ASU may be useful as a vehicle for acquiringspectra of samples required for development of property model data sets,though it may be used for other purposes as well.

The ASU may be used in conjunction with the SSU when the MRA is online.Alternatively, the ASU may be used with the MRA in an offline modewithout the SSU. Whether offline or online, a flowing sample at theanalysis set point temperature may be desired to effect shimming(tuning) of the MRA magnet. For online implementations, a sample streamsupplied through a fast loop may be used for this purpose. However, suchsample streams generally have variable composition, which may lead toinconsistent shimming. Furthermore, it is well established in NMRspectroscopy that compounds having an NMR spectrum consisting of asingle peak tend to provide the best results during shimming.Consequently, uncertainty of the shimming process may be compounded bythe multiple peaks generally found in the typical process sample. Inoff-line mode, provision of such a stream has been difficult andgenerally impractical. Therefore, in embodiments of the presentinvention, the SRU may be used to circulate an appropriate, single-peakreference solvent through the MRA (e.g., through the MRA's flow-pipeprobe) at the desired set point temperature.

For the MRA, water injected manually (i.e., at ambient temperature) intothe flow-pipe probe at ambient temperature has been an established shimstandard. However, it has also been the practice to further adjust(e.g., further shim) the MRA using a process stream (e.g., at thedesired set point temperature) as described above, to optimizespectrometer performance following thermal equilibration at the analysisset point. Embodiments of the SRU are thus designed to facilitateshimming on water at analysis set point temperatures above ambient.However, because water is not compatible with hydrocarbon streamscommonly analyzed with the MRA, the SRU can also deliver otherprocess-compatible, (e.g., single-peak) standards to the MRA. Examplesof these other standards include cyclohexane and ortho-xylene. Finally,in the case of heavy or dirty samples that may deposit residue insidethe MRA (e.g., within the MRA's flow-pipe probe), the SRU may be used todeliver to the MRA flow-pipe probe an appropriate cleaning solvent,which may or may not be the same as the shim standard.

The SSU and SRU thus represent technologies that facilitate preciseoperation of, and spectral measurement by the MRA, while the ASUfacilitates the rapid development of calibration sample data setsrequired for the development of property models. All three of theseaspects tend to enhance precision in spectral measurement relative toprior approaches, through precise temperature control of materialsdelivered to the MRA for analysis. The ASU is particularly helpful inthis regard because it helps to ensures the representative presentationto an analyzer of samples that may tend to stratify, separate, orotherwise become inhomogeneous over a relatively short time frame.Embodiments of the ASU thus permit offline measurement of spectra for apopulation of samples spanning the range of properties and chemistriescharacteristic of the process. Samples may thus be pre-collected (e.g.,collected while the MRA is offline or otherwise unavailable), and maythen be measured in a relatively short time frame following analyzerstartup. Additionally, after the calibration data set has been developedand the analyzer is online and operational, the ASU may be employed toinject a ‘standard’ (check) sample, for verifying ongoing performanceaccuracy, and/or during system maintenance.

Referring now to the Figures, embodiments of the present invention willbe more thoroughly described.

Turning now to FIGS. 1A-1D, various embodiments of the present inventionare shown and described. One such embodiment is shown at 9 in FIG. 1A.In this embodiment, as system 9 includes an actively controlled, directcontact heat exchanger 36 configured for being coupled in upstreamserial fluid communication with a magnetic resonance analyzer 16. System9 also includes a controller 17 communicably coupled to heat exchanger36. Controller 17 may include substantially any microprocessor-baseddevice such as a PC, PLC (Programmable Logic Controller), or otherdevice commonly used for process automation. As also shown, heatexchanger 36 is disposed downstream of at least one fluid handler whichmay include a stream selection unit (SSU) 10, a solvent/standardrecirculation unit (SRU) 12, and/or an auto-sampling unit (ASU) 14.

As shown, SSU includes a plurality of stream input ports 19, a streamoutput port 21, and one or more valves 34 configured to selectivelycouple individual ones of the stream input ports 19 to the stream outputport 21. Controller 17 is configured to selectively actuate valves 34 toselect and couple a stream source entering through ports 19 to outputport 21, and to actuate the heat exchanger 36 to maintain a sample ofthe stream source at a predetermined temperature.

As also shown, SRU 12 includes one or more solvent/standard reservoirs50, 52, a fluid output port 21 associated with each of the reservoirs,and one or more valves 34 coupled to the output ports, to selectivelycouple an individual one of the fluid output ports 21 to heat exchanger36. Controller 17 is configured to selectively actuate the valves 34 tocouple a reservoir 50, 52 to the heat exchanger 36, and to actuate heatexchanger 36 to maintain a sample of solvent/standard at a predeterminedtemperature for input into the analyzer 16. A return line 23 isconfigured to return the solvent/standard sample to the reservoirs fromanalyzer 16.

ASU 14 includes one or more sample reservoirs 78, 78′ configured tostore samples therein, and a sample port 79 respectively coupledthereto. Sample reservoirs 78, 78′ each have a sample transfer pathway102 coupled to the sample port and extending into the reservoir, thepathway having a plurality of orifices 104 disposed at spaced locationsalong a length thereof. One or more ASU valves 90 selectively couple thesample ports 79 to heat exchanger 36. Controller 17 is configured toselectively actuate the ASU valves 90 to enable a sample to flow throughsample pathway 102 to the heat exchanger, and to actuate the heatexchanger to maintain the sample at a predetermined temperature. Variousaspects of this system 9 will be discussed in greater detailhereinbelow.

Referring now to FIGS. 1B-1D, particular variations of system 9 areshown as systems 109, 209, and 309. System 109 includes an exemplaryfluid flow configuration in which ASU 14 is disposed upstream of SSU 10,which in turn, is disposed upstream of SRU 12. Sample orsolvent/standard streams are then passed from SRU 12 to heat exchanger36. In FIG. 1C, system 209 includes only two of the aforementioned fluidhandler types, namely, an SSU 10 and an ASU 14 disposed upstream of heatexchanger 36. In FIG. 1D, system 309 also uses only two of the fluidhandler types: an SRU 12 and an ASU 14.

It should be recognized that the foregoing configurations are merelyexemplary, and that the various fluid handlers (SSU, SRU, and ASU)described herein, may be used alone or in nominally any combination,along with heat exchanger 36 and processor 17, to supply fluid to ananalyzer 16 in accordance with the present invention. Variousadditional, optional aspects of the present invention will now bedescribed in greater detail.

A. Stream Switching Unit (SSU)

Referring to FIG. 1E, an embodiment of the Stream Switching Unit (SSU),shown at 10′ is configured to permit online analysis of refinery streamsranging from gasoline, gasoline blendstocks, and light distillates toheavy hydrocarbons such as crude oil, vacuum gasoil, or FCC feed. Itsequentially selects between fast loops carrying sample, and thermallyconditions each to meet the temperature specification of the MRA priorto analysis.

1. Design and Operation.

-   -   In the particular embodiment shown, SSU 10′ is integrated into a        cabinet 18, and is configured to select and thermally condition        the sample before delivery to the MRA 16. Upon entering the SSU        10′, fast flow inputs 20 pass through flow meters 28 (and/or        flow controllers, not shown), which maintain consistent flow,        and through a self-cleaning ‘T’ filter 32. Sample may also,        optionally, be inputted into SSU 10′ by ASU 14 as shown in        phantom. Sample drawn from the fast loop through the filter 32,        or from optional ASU 14, passes through double block and bleed        valves 34 (e.g., in multi-stream embodiments, as shown) for        stream selection, which is then passed through an actively        controlled, direct contact (e.g., low thermal mass) heat        exchanger 36 (discussed hereinbelow) prior to delivery to MRA        16. After being analyzed by the MRA, the fluid is passed to a        flow meter 28 and flow controller 36 integrated into the SSU        10′, to help maintain consistent flow. This spent sample exiting        the MRA 16 may then be sent to an optional sample recovery        system 38 (shown in phantom) and/or back to the process, such as        via Return 40.

2. Temperature Control.

-   -   In a representative embodiments, the temperature of sample        arriving at the SSU from the fast loop (T_(fl)) falls within a        range between set point (T_(s)) plus zero ° C. and minus 30° C.        (T_(fl)=T_(s)+0° C. to T_(s)−30° C.). Thus, for example, crude        oil to be analyzed at a nominal temperature of 80° C. must        arrive at the SSU between 50° C. and 80° C. (155° F. and 175°        F.). Sample in the fast loop has a predetermined nominal flow        rate, which in this particular example, is about 3.8 L/min. (For        purposes of discussion here and in other sections below, the        sample analysis temperature will be taken to be 80° C., although        higher or lower temperatures may be used as appropriate.)    -   Temperature control inside the cabinet is achieved by means of a        dedicated heater 42, which maintains the cabinet internally at        the desired set point, e.g., 80° C. (175° F.) to help minimize        any temperature losses of the sample fast loop flow. A suitable        actively controlled, direct contact (and low-thermal-mass) heat        exchanger 36, is model No. 1-57-76-1 (240 volts, 1850 watts)        available from Watlow-Hannibal (An operating unit of Watlow Mo.)        of Hannibal Mo., which performs final thermal “polishing” to        ensure that the selected sample stream flowing to the MRA is        within the predetermined temperature tolerance (e.g., of        ±2.5° C. in particular embodiments). This direct contact heat        exchanger provides a heating element in direct contact with the        sample stream, rather than with another fluid. This direct        contact, in combination with the active, thermostatic        temperature control, and configuration of the fluid handlers as        described herein, provides relatively rapid temperature response        over a relatively wide range of temperatures, at relatively high        flow rates. For example, the nominal flow rate of the heat        exchanger 36 is 1 L/min. At this flow rate, the temperature        recovery time associated with switching between streams at        50° C. and 80° C. is less than 8 seconds, or, in particular        embodiments, approximately 5 seconds, or less, which is short        enough to avoid disrupting the thermal equilibrium of the MRA        flow-pipe probe and related hardware. Moreover, this        configuration permits various streams, at various distinct input        temperatures, to be successfully selected and their temperatures        “polished”, to enter the MRA at the predetermined temperatures.

3. Input for System Flush/Clean and MRA Shimming.

-   -   For crude oil applications, a minimum of one light stream such        as diesel or kerosene may be provided in addition to the crude        sample fast loop to permit periodic cleaning of the flow-pipe        probe in the MRA and lines leading to it. This same stream, or        any such process stream, may be used in the aforementioned        shimming process.

B. Solvent (Sample) Recirculation Unit (SRU)

Referring to FIG. 2, embodiments of SRU 12, 12′ are configured tothermally condition either a process sample or standard/solvent in areservoir during closed-loop recirculation (via return line 23) to theMRA 16. An objective of the SRU is to supply the MRA 16 with ashim/calibration material (e.g., water, via cylinder 50 as shown, oroptionally, some other reference material such as cyclohexane, whose NMRspectrum, like water, preferably exhibits a single peak) for shimmingthe magnet of the MRA 16 as discussed hereinabove. This is accomplishedwhile maintaining temperature and flow at levels nominally matchingthose of sample arriving from the SSU 10, 10′. Additionally, the SRU 12′may be used to provide pre-heated solvent, via cylinder 52, to the MRA16 to clean its flow-pipe probe, and/or for use as a secondaryshim/calibration material, as discussed in greater detail hereinbelow.

1. Design and Operation.

-   -   In the embodiment shown, SRU 12′ includes a cabinet 54 with a        cabinet heater 42 (e.g., as used in the SSU 10′), one or more        insulated and heat-jacketed cylinders or canisters 50, 52 (e.g.,        fabricated from aluminum or other suitable material to        facilitate heat transfer); a low-thermal-mass, actively        controlled, direct contact heat exchanger 36 (e.g., as used in        the SSU 10′); and a recirculation pump 56 disposed either within        cabinet 54 or outside the cabinet as shown. Appropriate utility        connections (not shown) supply needed electrical power and/or        air to actuate valves 34 used to selectively couple the flow        from canisters 50, 52 to heat exchanger 36. Additionally, water        and shim/cleaning solvent supplies (the latter, for example,        being under nitrogen pressure) are respectively connected to        inputs 58, 60, for filling the canisters. Provision may be is        made, e.g., in the form of pressure relief valves (not shown) to        accommodate expansion of the fluid upon heating from ambient to        the set point.    -   Prior to shimming/calibration, a procedure may be implemented by        which alternate “shots” of pre-heated nitrogen and solvent are        delivered through the system to displace fluid (e.g., previously        analyzed sample material) from the transfer lines and MRA 16.        Nitrogen used for this purpose would flow through suitable lines        inside SRU 12′.    -   In operation, canister 52 is provided with a solvent that is        compatible with the particular process fluid to be analyzed by        MRA 16. (The solvent may also be used for shimming, as described        below.) Due to the high efficiency of the actively controlled,        direct contact heat exchanger 36 as used in this exemplary        embodiment, for an analysis set point of, e.g., 80° C., solvent        (or water) may enter the heat exchanger 36 as low as about 50°        C., to reduce the requirement to preheat and maintain a quantity        of solvent (or water) at 80° C. within canisters 50, 52.    -   In particular embodiments, valves 34 may be operated to provide        water from canister 50 at the desired temperature (at e.g. 80°        C.), for shimming the MRA 16, followed by a second shimming        operation using the solvent in canister 52, also at the desired        temperature. In particular embodiments, the solvent may be        cyclohexane, toluene, or ortho-xylene, which also serves as a        process-compatible reference (standard) that can be used        frequently to demonstrate the repeatability of spectral        measurement (i.e., the stability of the MRA's spectral        response).    -   This approach eliminates the variations due to temperature        differences experienced during conventional two-step shimming        operations, in which water at ambient temperature is provided        for the first shimming operation, followed by a second shimming        operation using a temperature-controlled process stream, e.g. at        80° C., to compensate for any changes in the spectrometer        response, such as may attend the temperature change. Moreover,        embodiments of the present invention may be used to        advantageously eliminate the need for a two-step shimming        operation, by eliminating the need for shimming with water.        Instead, MRA 16 may simply be shimmed using cyclohexane or some        other reference/standard (e.g., at the desired process        temperature) whose NMR spectrum, like water, exhibits a single        peak. In this regard, however, it should be recognized that        although reference/standards exhibiting a single peak may be        desired in many applications, materials exhibiting multiple        peaks may also be used for shimming in other applications.

2. Temperature Control.

-   -   Embodiments of SRU 12′ are capable of maintaining temperatures        at predetermined levels, e.g., between 40° C. and 100° C. Lower        temperatures may be appropriate for lighter hydrocarbon samples        such as gasoline, while crude oil is preferably analyzed at        80° C. to prevent waxing. Still higher temperatures may be        required for heavier materials such as vacuum gasoil. Cylinders        made of aluminum rather than stainless steel, if suitable for        prolonged contact with the particular fluid used, at the        particular temperatures concerned, may be used to improve heat        transfer to the solvent, as mentioned above.

3. Offline or Online Use.

-   -   The SRU may be used alone, or in conjunction with either the ASU        14, 14′ or the SSU 10 as shown. Moreover, when used with SSU 10,        hybrid approaches may be used, such as for online applications        in which the SRU 12′ may be used without running the        solvent/sample supply through the SSU prior to analysis, but is        otherwise controlled by controller 17, such as may be integrated        with the MRA 16. In such a configuration, solvent may be        re-circulated back to SRU 12′ via SSU 10 as shown, or may be        discarded after use by the MRA 16, e.g., for recycling.    -   For offline projects, samples may be injected directly into the        MRA 16 from the ASU 14′ (as discussed hereinbelow), while the        SRU interfaces separately to the MRA 16, for solvent supply.

C. Auto-Sampling Unit (ASU)

Referring now to FIG. 3, a more detailed, representative embodiment ofan ASU in accordance with the present invention is shown at 14′. Asdiscussed above, the various embodiments of the ASU may be operated withthe MRA 16 independently or in combination with SSU 10, 10′ or SRU 12,12′. In the embodiment shown, ASU 14′ may be used to preheat multiplesamples (e.g., up to five samples as shown) contained in separatecylinders 70, 72, 74, 76 and 78, respectively, to facilitate automaticacquisition of sample spectra for simplified, reliable model developmentor validation. (Optional secondary cylinders 70′, 72′, 74′, 76′ and 78′,as shown in phantom, will be discussed in greater detail hereinbelow,with reference to FIG. 4.)

1. Temperature Control and Operation.

-   -   In particular embodiments, the ASU 14′ includes a heated cabinet        64 (e.g., heated by one or more cabinet heaters 42) and sample        cylinder heaters 80 to thermally condition samples at        temperatures from 40° C. to 80° C. (104° F. to 175° F.). In the        example shown, five two-liter sample cylinders A are        close-coupled to sample cylinder heaters 80 to promote efficient        heat transfer, to minimize the time required to achieve the        desired temperature. (The heaters 80 may be in the form of a        suitable heating blanket, which is then covered by a jacket        providing thermal insulation. Temperature controllers 82, in        conjunction with thermocouples or other temperature sensors 106        (FIG. 7) may be used to monitor the surface temperature of the        heater, the cylinder, and the cylinder contents.)    -   In preliminary tests, examples of ASU 14′ provided a heating        rate of approximately 1° C. per minute, so that samples were        heated from ambient to 80° C. in approximately one hour. By        contrast, calculations suggested that heating the same sample in        unclad cylinders could take 48 hours if accomplished solely by        means of maintaining the atmosphere in the cabinet at 80° C. A        controller 82, that monitors the temperature of the heaters 80,        the cylinders, and the sample, may also control electrical power        to the heaters 80, to provide an initial, high heating rate,        followed by diminished thermal input as sample approaches the        set point temperature. Moreover, a fast-response, low        thermal-mass sample heater, such as heat exchanger 36 used with        SSU 10′ and SRU 12′ discussed above, may be used to reduce        (e.g., from 80° C. to 50° C. or less) the requirement for sample        preheating.    -   As also shown, a series of three way valves 84 are coupled to        the bottom of each cylinder 70, 72, etc., to control and direct        the flow of sample within the ASU and output therefrom (e.g., to        the MRA 16, optionally via SSU 10′. Valves 86 at the tops of the        cylinders control the supply of gas (e.g., nitrogen, instrument        air or helium) from a gas supply 88, used to displace samples        from the cylinders for subsequent analysis by the MRA 16.        External connections are provided for coupling to the gas supply        88 (e.g., of at least about 80 psi) and electrical power for the        heaters 42, 80. The system may be closely coupled to the MRA 16        to minimize the length of the (e.g., heat traced) tubing        therebetween, and to help maintain a constant flow of        temperature-controlled sample.

2. Option for Crude Mixing

-   -   As mentioned hereinabove, at elevated temperature where        viscosity is reduced, non-homogeneous materials such as crude        oil and the like have a tendency to stratify during the time        required for thermal equilibration. Therefore, in applications        involving these materials, it may be desirable to provide ASU        14′ with the ability to homogenize these materials prior to        injection into the MRA 16. As best shown in FIG. 4, an optional        variation of ASU 14′ is described, which effectively mixes crude        oil or other non-homogeneous samples that may otherwise tend to        separate/stratify during thermal conditioning prior to analysis.

a. Cyclone Mixer.

-   -   In this embodiment, the size of the cabinet 64 (FIG. 3) is        increased to accommodate the pairing of additional cylinders        70′, 72′, etc., with sample cylinders 70, 72, etc.,        respectively. One representative pairing is shown and described        as 70, 70′ (or cylinders A & B) in FIG. 4. Oriented vertically,        the cylinders are connected to each other by means of tubing and        valves 90 at the bottom; while valves 92 at the top permit        either the delivery of a suitable gas (e.g., nitrogen,        instrument air, or helium) from supply 88 (FIG. 3) for        pressurization, or the venting of gas to relieve pressure.    -   Displacement Mixing. With reference to FIGS. 4-6, mixing may be        accomplished by pressurizing cylinder A (70) using gas from gas        supply 88, and opening the valve 90 to permit displacement of        sample into cylinder B (70′). As best shown in FIGS. 5 &6, a        sample inlet tube 94 is provided to deliver sample to the        interior of cylinder B (70′). A proximal end of tube 94 is        fastened to the cylinder inlet. The tube extends from the        proximal end toward the distal end, generally curving radially        outward towards the periphery of the cylinder. In particular        embodiments, the curvature is configured so that the distal end        of tube 94 is substantially tangent to the inside surface of the        cylinder on a plane substantially perpendicular to the cylinder        axis, approximately 10-50 percent of the distance from the        bottom to the top of the cylinder as shown. As a result, sample        entering cylinder B (70′) does so in a direction substantially        perpendicular to the cylinder axis and flows along the inside        surface of the cylinder, creating a radial flow facilitating the        mixing of sample.    -   Prior to injection, Cylinder B may be purged with an        appropriate, dry gas, e.g., from gas supply 88 (FIG. 4). Helium        may be preferred for some applications, as some processes are        sensitive to nitrogen or oxygen; and since helium is        substantially insoluble in liquids, its use tends to eliminate        off-gassing and the formation of bubbles upon reduction of        sample pressure, which might otherwise occur in the event a more        soluble gas were used for the same purpose.    -   As sample fills cylinder B (70′), it compresses the gas therein        (since valve 92 has been closed). (Depending on the pressure        applied to Cylinder A (70), a pressure relief valve (not shown)        may or may not be required to permit venting of the gas through        the valve 92 at the top of the cylinder 70′ and to facilitate        the aforementioned displacement of sample into Cylinder B (70′)        through the tube 94.) Because materials such as crude oil        contain volatile components that boil below 80° C. at ambient        pressure, adequate pressure must be maintained to prevent        boiling/distillation of these components during filling of        cylinder B (70′). Additionally, the initial flow rate should be        relatively slow until the distal end of the inlet tube is        submerged so as to minimize the distribution of sample on the        inside surface of the cylinder above the level of the sample. To        accomplish this, gas supply 88 may use dual-regulators, e.g.,        including both low and high pressure regulators 98 & 100,        respectively, to apply low pressure initially, and subsequently        provide higher gas pressure to produce higher flow rates as may        be desired to facilitate mixing and to overcome pressure        build-up within cylinder B (70′).    -   Since sample initially filling cylinder B (70′) may not be        representative of the bulk sample in cylinder A (70), the inlet        tube 94 may be provided with a relatively small hole 96 (FIG. 5)        near its proximal end just inside the cylinder to facilitate        upward displacement of sample that may otherwise collect at the        bottom of cylinder B (e.g., below the distal end of the inlet        tube 94). The geometry of the distal end of the inlet tube 94        may also be formed as desired, such as in the form of a nozzle,        to increase the velocity of sample entering cylinder B        therefrom, and to create back-pressure sufficient to promote        desired levels of flow through the hole 96.    -   Displacement/Delivery to the MRA. Once sufficient mixing has        taken place in cylinder B (70′), valve 90 may be closed, and        valve 84 associated with the particular cylinder pair 70, 70′        may be opened to allow displacement of sample from cylinder B        into the MRA 16 (e.g., either directly, or via SSU 10′). In this        regard, gas pressure is applied through valve 92 to drive the        sample back out through the inlet tube 94.

b. Distributed Sampling During Sample Displacement.

-   -   Turning now to FIG. 7, as a further alternative embodiment, a        cylinder A (shown as 170) may be provided with a tube 102        attached to its lower outlet. The tube is generally long enough        to extend along at least 50 percent or more of the length of the        cylinder, and in particular embodiments, at least part way into        the tapered end to help limit any lateral movement of the tube        102. A plurality of holes (orifices) 104 are spaced along the        length of the tube 102 to permit sample to flow into the tube        102 from multiple levels in cylinder A (170), i.e. to facilitate        “distributed sampling.” The spacing and/or diameter of the holes        104 may be varied from bottom to top to help maintain the flow        rate of sample displaced through each hole nominally constant,        e.g., regardless of the total amount of sample remaining in the        cylinder. As in the case of the sample inlet tube 94 in cylinder        B, a hole 96 may be provided at the base of tube 102 to help        ensure that sample is displaced in a quantitative and        representative fashion. Cylinder 170 may be provided with a        temperature sensor, such as a thermocouple 106 as shown.

c. Flow-Through Cyclone Mixing Chamber.

-   -   Referring to FIG. 8, it is expected that in many applications,        the aforementioned distributed sampling provided by the use of        tube 102, may provide sample whose composition remains        substantially constant as the cylinder 170 is drained. In such        applications, it may not be necessary to subsequently send the        sample into a cylinder B (70′, 170) for subsequent mixing as        described above, but rather, the sample may be injected directly        from cylinder A (70) into the MRA 16 (or SSU 10′).    -   Alternatively, rather than quantitatively displace all the        contents of cylinder A into cylinder B, and then from cylinder B        to the MRA 16, a smaller receiving cylinder B′ may instead        function as a flow-through mixing chamber 270. With a volume of        about 10%-25% that of cylinder A (70), sample displaced        continuously from cylinder A would fill B′ and dynamically mix        within B′ en route to the MRA 16 (or SSU 10′). A curved inlet        tube 94 such as described above with respect to cylinder B        (70′), or lengthened as shown at 94′ to extend helically along        substantially the length of cylinder 270, may be provided. Tube        94, 94′ may also be used in combination with a perforated drain        tube 102 as described above with respect to FIG. 7 (but        inverted, so that sample exits from the top), to facilitate the        quantitative filling of B′ while A is emptied.    -   The volume of B′ would be sized appropriately to dampen the        magnitude of the transient inhomogeneity experienced while        draining the contents of A. For this approach, transient        inhomogeneity in many applications should average to constant        composition across the e.g., 2-liter volume drained from A, i.e.        a line regressed through a plot of composition versus drained        volume should have a slope approximately equal to zero, as shown        in FIG. 9. In practice, it may be desirable to fill B′ (270)        from the bottom, and the sample would be allowed initially to        exit through the top to displace gas being closed.

3. Alternative Uses of the ASU.

It is contemplated that embodiments of the ASU 14, 14′ will be usedprimarily as an aid for building and validating a property model asdiscussed hereinabove, i.e., it permits offline measurement of spectrafor a population of samples spanning the range of properties andchemistries characteristic of the process. Samples collected while theMRA is offline, e.g., before installation of the MRA 16, may be measuredin a relatively short time frame following MRA startup. Additionally,after the calibration data set has been developed and the MRA is onlineand operational, the ASU may be employed to inject a ‘standard’ (check)sample (e.g., via SSU 10′) for ongoing performance verification orduring system maintenance. Finally, in the case of heavy or dirtysamples that may deposit residue inside the MRA 16, the ASU may be usedto flush the analyzer system with an appropriate cleaning solvent.

It should be understood that any of the features described with respectto one of the embodiments described herein may be similarly applied toany of the other embodiments described herein without departing from thescope of the present invention.

In the preceding specification, the invention has been described withreference to specific exemplary embodiments for the purposes ofillustration and description. It is not intended to be exhaustive or tolimit the invention to the precise form disclosed. Many modificationsand variations are possible in light of this disclosure. It is intendedthat the scope of the invention be limited not by this detaileddescription, but rather by the claims appended hereto.

1. An apparatus for spectroscopic sample analysis, the apparatuscomprising: an actively controlled, direct contact heat exchangerconfigured for being disposed in upstream serial fluid communicationwith a spectroscopic analyzer; a controller communicably coupled to saidheat exchanger; and said heat exchanger disposed in serial fluidcommunication downstream of at least one fluid handler selected from thegroup consisting of: a stream selection unit (SSU) including: aplurality of stream input ports; a stream output port; one or more SSUvalves configured to selectively couple individual ones of said streaminput ports to said stream output port; wherein said controller isconfigured to selectively actuate said one or more SSU valves to selectand couple a stream source to the stream output port, and actuate theheat exchanger to maintain a sample of said stream source at apredetermined temperature; a solvent/standard recirculation unit (SRU)including: one or more solvent/standard reservoirs; a fluid output portrespectively associated with each of said one or more reservoirs; one ormore SRU valves coupled to said output ports, to selectively couple anindividual one of said fluid output ports to said heat exchanger; saidcontroller being configured to selectively actuate individual ones ofthe SRU valves to couple a reservoir to the heat exchanger, and actuatethe heat exchanger to maintain a sample of solvent/standard at apredetermined temperature for input into the analyzer; and a return lineconfigured to return the solvent/standard sample to the reservoirs fromthe analyzer; and an auto-sampling unit (ASU) including: one or moresample reservoirs configured to store one or more samples therein; asample port respectively coupled to each of said reservoirs; said samplereservoirs each having a sample transfer pathway coupled to said sampleport and extending into said reservoir; said pathway having a pluralityof orifices disposed at spaced locations along a length thereof; one ormore ASU valves configured to selectively couple said sample port tosaid heat exchanger; wherein said controller is configured toselectively actuate said one or more ASU valves to enable a sample toflow through the sample pathway to the heat exchanger, and to actuatethe heat exchanger to maintain said sample at a predeterminedtemperature.
 2. The apparatus of claim 1, comprising the spectroscopicsample analyzer disposed in serial fluid communication with said heatexchanger.
 3. The apparatus of claim 1, comprising at least two of thefluid handlers selected from the group consisting of said SSU, said SRU,and said ASU.
 4. The apparatus of claim 3, comprising an SSU and an ASUdisposed upstream of said heat exchanger.
 5. The apparatus of claim 4,comprising an SRU disposed upstream of said heat exchanger.
 6. Theapparatus of claim 1, comprising a pump disposed in serial fluidcommunication with said heat exchanger.
 7. The apparatus of claim 6,comprising an SRU disposed upstream of said heat exchanger, wherein saidpump is configured to return solvent/standard exiting the analyzer tosaid SRU.
 8. The apparatus of claim 7, comprising an ASU disposedupstream of said heat exchanger.
 9. The apparatus of claim 8, comprisingan SSU, wherein said ASU is disposed upstream of said SSU.
 10. Theapparatus of claim 1, wherein said controller is configured toselectively actuate individual ones of said ASU valves to fill saidsample/standard reservoirs through said sample ports.
 11. The apparatusof claim 10, comprising a gas port coupled to each of said samplereservoirs, the gas port configured for selectively receiving gastherein, to occupy volume within the sample reservoirs vacated by sampleexiting through said sample ports.
 12. The apparatus of claim 11,wherein each reservoir comprises an other sample transfer pathwayextending from a proximal end coupled to said sample port, to a distalend disposed within said reservoir, said distal end having a centralaxis extending obliquely relative to a longitudinal axis of saidreservoir.
 13. The apparatus of claim 12, wherein said other sampletransfer pathway has a plurality of orifices disposed at spacedlocations along a length thereof.
 14. The apparatus of claim 12, whereinsaid reservoir comprises first and second chambers coupled to oneanother, said sample transfer pathway being disposed in said firstchamber, and the other sample transfer pathway being disposed in saidsecond chamber.
 15. A sample handling apparatus comprising: a streamselection unit (SSU) including: a plurality of stream input ports; astream output port; one or more SSU valves configured to selectivelycouple individual ones of said stream input ports to said stream outputport; a pump disposed in serial fluid communication with said streamoutput port; an actively controlled, direct contact heat exchangerdisposed in series with said stream output port; a controller configuredto selectively actuate said pump and said one or more SSU valves toselect and couple a stream source to the stream output port, and actuatethe heat exchanger to maintain a sample of said stream source at apredetermined temperature for input to a spectroscopic analyzer;
 16. Thesample handling apparatus of claim 15, comprising: a spectroscopicanalyzer coupled to said stream output port.
 17. A sample handlingapparatus comprising: a solvent/standard recirculation unit (SRU)including: one or more solvent/standard reservoirs; a fluid output portrespectively associated with each of said one or more reservoirs; one ormore SRU valves coupled to said output ports, to selectively couple anindividual one of said fluid output ports to said heat exchanger; a pumpdisposed in serial fluid communication with said fluid output port; anactively controlled, direct contact heat exchanger disposed in serieswith said fluid output port; a controller configured to selectivelyactuate individual ones of the SRU valves to couple the solvent/standardreservoirs to the heat exchanger, to actuate the pump, and to actuatethe heat exchanger to maintain a sample of solvent/standard at apredetermined temperature for input into a spectroscopic sampleanalyzer; and a return line configured to return the solvent/standardsample to the reservoirs from the analyzer.
 18. The sample handlingapparatus of claim 17, comprising: the spectroscopic sample analyzercoupled to said analyzer connection ports.
 19. A sample handlingapparatus comprising: an auto-sampling unit (ASU) including: one or moresample reservoirs configured to store one or more samples therein; asample port respectively coupled to each of said reservoirs; said samplereservoirs each having a sample transfer pathway coupled to said sampleport and extending into said reservoir; said pathway having a pluralityof orifices disposed at spaced locations along a length thereof; anactively controlled, direct contact heat exchanger disposed in serieswith said sample port; one or more ASU valves configured to selectivelyopen and close a fluid flow path between said sample port and said heatexchanger; a controller configured to selectively actuate said one ormore ASU valves to enable a sample to flow through the sample pathway tothe heat exchanger for input into a spectroscopic sample analyzer, andto actuate the heat exchanger to maintain said sample at a predeterminedtemperature.
 20. The apparatus of claim 19, wherein said controller isconfigured to selectively actuate individual ones of said ASU valves tofill said sample/standard reservoirs through said sample ports.
 21. Theapparatus of claim 20, comprising a gas port coupled to each of saidsample reservoirs, the gas port configured for selectively receiving gastherein, to occupy volume within the sample reservoirs vacated by sampleexiting through said sample ports.
 22. The apparatus of claim 21,wherein each reservoir comprises an other sample transfer pathwayextending from a proximal end coupled to said sample port, to a distalend disposed within said reservoir, said distal end having a centralaxis extending obliquely relative to a longitudinal axis of saidreservoir.
 23. The apparatus of claim 22, wherein said reservoircomprises first and second chambers coupled to one another, said sampletransfer pathway being disposed in said first chamber, and the othersample transfer pathway being disposed in said second chamber.
 24. Thesample handling apparatus of claim 19, comprising: a spectroscopicsample analyzer coupled to said sample port.
 25. A method ofspectroscopic sample analysis, the method comprising: (a) disposing anactively controlled, direct contact heat exchanger in upstream serialfluid communication with a spectroscopic sample analyzer; (b)communicably coupling a controller to the heat exchanger; and (c)disposing the heat exchanger in serial fluid communication downstream ofat least one fluid handler selected from the group consisting of: astream selection unit (SSU) including: a plurality of stream inputports; a stream output port; one or more SSU valves configured toselectively couple individual ones of said stream input ports to saidstream output port; wherein said controller is configured to selectivelyactuate said one or more SSU valves to select and couple a stream sourceto the stream output port, and actuate the heat exchanger to maintain asample of said stream source at a predetermined temperature; asolvent/standard recirculation unit (SRU) including: one or moresolvent/standard reservoirs; a fluid output port respectively associatedwith each of said one or more reservoirs; one or more SRU valves coupledto said output ports, to selectively couple an individual one of saidfluid output ports to said heat exchanger; said controller beingconfigured to selectively actuate individual ones of the SRU valves tocouple a reservoir to the heat exchanger, and actuate the heat exchangerto maintain a sample of solvent/standard at a predetermined temperaturefor input into the analyzer; and a return line configured to return thesolvent/standard sample to the reservoirs from the analyzer; and anauto-sampling unit (ASU) including: one or more sample reservoirsconfigured to store one or more samples therein; a sample portrespectively coupled to each of said reservoirs; said sample reservoirseach having a sample transfer pathway coupled to said sample port andextending into said reservoir; said pathway having a plurality oforifices disposed at spaced locations along a length thereof; one ormore ASU valves configured to selectively couple said sample port tosaid heat exchanger; wherein said controller is configured toselectively actuate said one or more ASU valves to enable a sample toflow through the sample pathway to the heat exchanger, and to actuatethe heat exchanger to maintain said sample at a predeterminedtemperature; (d) with the controller, actuating the at least one fluidhandler to enable a sample to flow therethrough to the heat exchanger;(e) with the controller, actuating the heat exchanger to maintain thesample at the predetermined temperature; and (f) supplying the sample atthe predetermined temperature, to the sample analyzer.